This section is intended to provide background information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.
Wells are drilled at various depths to access and produce oil, gas, minerals, and other naturally-occurring deposits from subterranean geological formations. The drilling of a well is typically accomplished with a drill bit that is rotated within the well to advance the well by removing topsoil, sand, clay, limestone, calcites, dolomites, or other materials. The drill bit is attached to a drill string that may be rotated to drive the drill bit and within which drilling fluid, referred to as “drilling mud” or “mud,” may be delivered downhole. The drilling mud is used to cool and lubricate the drill bit and downhole equipment and is also used to transport any rock fragments or other cuttings to the surface of the well. The drill string may include a bottom hole assembly (BHA) that includes various electronic tools such as motors, directional sensing devices, generators, and the like.
As wells are established it is often useful to obtain information about the well and the geological formations through which the well passes. Information gathering may be performed using tools that are delivered downhole by wireline, tools coupled to or integrated into the drill string, or tools delivered on other types of testing strings. These tools may include logging while drilling (LWD) and measurement while drilling (MWD) tools. Testing strings, which may be used to test a well, include tools such as tester valves, circulations valves, and the like. Many of these downhole tools and devices include regions which need to remain sealed and isolated from fluid that may be present in the downhole environment.